1. Field of the Invention
The present invention relates to a photoelectric conversion device.
2. Description of the Related Art
To improve the quality of images captured by cameras such as a digital camera and a digital video camera, a photoelectric conversion device needs to widen the light detecting range at low illuminance. A photoelectric conversion device that inputs a current generated by a photoelectric converter to the base of a transistor, and outputs an amplified current from the emitter of the transistor has been disclosed (see Japanese Patent Laid-Open No. 2000-077644).
The light detecting range of the photoelectric conversion device described in Japanese Patent Laid-Open No. 2000-077644 is determined depending on the current generated per unit time, and the range in which a signal processing circuit in a subsequent stage can detect a signal. As a method of widening the light detection range, a method of reducing the current generated per unit time is available. Unfortunately, in this case, while the high-illuminance light detecting range widens, the low-illuminance light detecting range narrows because the latter range is limited by the range in which the signal processing circuit in a subsequent stage can detect a minute signal.